@article{da94ca84bf6a420d80c314d46b598a9e,
title = "Assessing Long-Term Postseismic Transients From GPS Time Series in Southern California",
abstract = "In order to gain insight into long-term plate boundary motion and to shed light on geodetic-based fault slip rates and the seismic hazards they inform, we apply a forward modeling strategy to identify and reduce the short- and long-term effects of viscoelastic postseismic deformation on modern GPS observations following large magnitude earthquakes in Southern California. We assess ongoing postseismic deformation in the southwestern United States by analyzing all magnitude ≥Mw6.0 earthquakes that have occurred there and in Baja California and Sonora, Mexico, since year 1800, finding that ongoing postseismic displacements from 12 events are potentially contributing to the modern day deformation field in Southern California. With a forward modeling step, we calculate postseismic displacements associated with these 12 events using a reference model consisting of a layered, laterally homogeneous, viscoelastic Earth structure; these displacements are then subtracted from processed horizontal GPS coordinate time series data to produce a postseismic-reduced data set. In order to quantify the success of this forward modeling in reducing the postseismic signal, we estimate parameters representing logarithmic decay associated with the 2010 Mw7.2 El Mayor-Cucapah earthquake using two different time series analysis methods. Variance reduction indicates we were able to reduce postseismic deformation in this test case by up to 60%. Anomaly maps produced using our assessment of deformation around the El Mayor-Cucapah event highlight hot spots in which secondary processes may be occurring or where a more complex viscosity structure may be necessary.",
keywords = "GPS, Southern California, postseismic deformation, time series",
author = "Guns, {K. A.} and Bennett, {R. A.}",
note = "Funding Information: Thanks to two anonymous reviewers for their thoughtful feedback that greatly improved this manuscript. We thank Sally McGill for sharing campaign GPS data from the San Bernardino Mountains with us before it was publically archived at UNAVCO through the Data Archive Interface v.1 (https://www.unavco.org/data/data.html); we also wish to thank all those patient souls from the University of Arizona who helped collect campaign GPS data from Joshua Tree National Park (thanks to Lisa Knowles, Clinton Koch, Carson Richardson, Audrey Dunham, Lauren Reeher, Ken Gourley, Terrance Delisser, Wit Nantonoi, Sean Callahan, Lauren Ward, Tommy Yong, Maria Snyder, Brooke Elser, and Gunnar Speth). In addition, we thank Jay Theuer and Luke Sabala from the National Park Service for their support and assistance in permitting our research within Joshua Tree National Park. We also thank James Broermann for his time and the many fruitful conversations we had concerning this research and the use of his meticulously calculated viscoelastic Earth model. We prepared many figures using GMT software (Wessel et al., 2013). GPS observation equipment was provided by UNAVCO and PBO facilities, for which we are grateful. Field work to collect campaign GPS data was funded by the Southern California Earthquake Center (Award 17161) and two Geological Society of America Graduate Student Research Grant awards (ExxonMobil Specialized Award and John T. and Carol G. McGill Specialized Award) to K. Guns and funding from the University of Arizona Department of Geosciences Dr. H. Wesley Peirce and Maxine W. Peirce Scholarship fund. Funding Information: Thanks to two anonymous reviewers for their thoughtful feedback that greatly improved this manuscript. We thank Sally McGill for sharing campaign GPS data from the San Bernardino Mountains with us before it was publically archived at UNAVCO through the Data Archive Interface v.1 ( https://www.unavco.org/data/data.html ); we also wish to thank all those patient souls from the University of Arizona who helped collect campaign GPS data from Joshua Tree National Park (thanks to Lisa Knowles, Clinton Koch, Carson Richardson, Audrey Dunham, Lauren Reeher, Ken Gourley, Terrance Delisser, Wit Nantonoi, Sean Callahan, Lauren Ward, Tommy Yong, Maria Snyder, Brooke Elser, and Gunnar Speth). In addition, we thank Jay Theuer and Luke Sabala from the National Park Service for their support and assistance in permitting our research within Joshua Tree National Park. We also thank James Broermann for his time and the many fruitful conversations we had concerning this research and the use of his meticulously calculated viscoelastic Earth model. We prepared many figures using GMT software (Wessel et al., 2013 ). GPS observation equipment was provided by UNAVCO and PBO facilities, for which we are grateful. Field work to collect campaign GPS data was funded by the Southern California Earthquake Center (Award 17161) and two Geological Society of America Graduate Student Research Grant awards (ExxonMobil Specialized Award and John T. and Carol G. McGill Specialized Award) to K. Guns and funding from the University of Arizona Department of Geosciences Dr. H. Wesley Peirce and Maxine W. Peirce Scholarship fund. Publisher Copyright: {\textcopyright}2020. American Geophysical Union. All Rights Reserved.",
year = "2020",
month = apr,
doi = "10.1029/2019JB018670",
language = "English (US)",
volume = "125",
journal = "Journal of Geophysical Research: Space Physics",
issn = "2169-9380",
publisher = "Wiley-Blackwell",
number = "4",
}